The spring auction season has got off to a mixed start, with the proportion of homes sold in September down from 2014.
Lower clearance rates reflect an increase in the number of owners seeking to sell their property, and indicate a greater choice for buyers but a more challenging environment for sellers.
"The first month of spring has provided mixed results, with all major capital cities except Adelaide reporting decreases in clearance rates over the month," property website Domain's senior economist Andrew Wilson said.
"September home auction activity is now generally tracking below last year's September levels."
Sydney's clearance rate dropped to 69.9 per cent in September, the lowest rate for the first month of spring since 2012.
Auction sales in Melbourne had a more modest drop from August, while Brisbane and Canberra's clearance rates suffered sharp falls from the prior month.
Adelaide's clearance rate of 65.3 per cent was barely higher than 65.2 per cent in August.
While sales rates are lower, prices have either risen or remained steady across capital cities.
"Record high volumes of auctions will continue to test capital city markets for the remainder of the year, providing greater competition amongst sellers and more choice for buyers," Dr Wilson said.
"This is likely to continue putting downward pressure on clearance rates, particularly in Sydney, and to a lesser degree Melbourne."